High-performance phenolic resin glue for preparing engineering bamboos and preparation method of high-performance phenolic resin glue

Abstract

The invention relates to high-performance phenolic resin glue for preparing engineering bamboos and a preparation method of the high-performance phenolic resin glue. The method comprises the following steps: adding gamma-aminopropyltriethoxysilane (APTES) and epoxy silane (KH-560) into an ethanol solution according to a certain proportion, uniformly mixing by adopting magnetic stirring, sequentially adding graphene nanosheets and Tween 80, and continuously stirring to prepare the modified phenolic resin. The obtained phenolic resin is excellent in bonding performance, has good mechanical strength and high temperature resistance, can further react with a bamboo substrate to enhance the interface bonding force, and is suitable for high-performance processing and manufacturing of bamboo products.

Description

Technical Field

[0001] The invention belongs to the field of engineering bamboo material processing, and particularly relates to a high-performance phenolic resin glue for preparing engineering bamboo and a preparation method thereof. Background Art

[0002] Global warming is primarily caused by greenhouse gases such as carbon dioxide (CO2), carbon monoxide (CO), and methane (CH4), with CO2 being one of the primary contributing factors. The construction industry accounts for over 8% of global CO2 emissions, and this proportion is expected to rise as infrastructure construction continues to expand. Therefore, the development of sustainable building materials has become a pressing issue. As traditional building materials, bamboo and wood are attracting renewed attention due to their lightweight, high-strength, and environmentally friendly advantages. However, due to factors such as rapidly growing demand for wood, increasing resource scarcity, and the strict implementation of natural forest protection policies, timber supply constraints are becoming increasingly prominent. Against this backdrop, bamboo, due to its short growth cycle, renewable nature, low cost, and high rigidity, is considered a potential alternative to wood. However, natural bamboo suffers from inherent drawbacks such as its small cross-sectional dimensions, thin walls, and hollow structure, resulting in significant radial fluctuations in its mechanical properties, making it difficult to meet the stability and load-bearing capacity requirements of modern construction. To overcome these issues, researchers have developed engineered bamboo materials, such as bamboo laminated timber. This type of material improves its dimensional stability through bonding and pressing, and optimizes the orientation of bamboo fibers, thereby reducing radial variability in mechanical properties. Although engineered bamboo materials offer some improvements in overall performance, they still face challenges in the preparation of large-scale integrated bamboo components. Traditional phenolic resins suffer from insufficient bonding and mechanical properties, making them difficult to meet the structural strength requirements of large-section components and prone to internal cracking, thus limiting their widespread application in practical engineering.

[0003] Research on modified phenolic resins has been carried out both at home and abroad. Patent CN104152088B discloses a method for preparing a nano-alumina modified phenolic resin adhesive, in which formaldehyde, phenol, sodium hydroxide, urea and nano-alumina are mixed to prepare the phenolic resin. The preparation process of the adhesive is very cumbersome, and in actual use, the components may crack, break and other phenomena, affecting the quality of the product. Patent CN105566590A discloses a method for preparing a modified phenolic resin and its application. This patent mainly improves the heat resistance stability through methyl oleate modification, but the improvement of other properties of the phenolic resin, such as toughness and flame retardancy, may be limited, and there is a problem of single performance improvement. Patent CN117511120A discloses a nano-modified phenolic resin-based composite material and its preparation method and application. This patent mainly focuses on improving the heat resistance and friction properties of the composite material, and may improve other properties of the phenolic resin-based composite material, such as mechanical properties and bonding properties, to a limited extent.

[0004] APTES molecules contain both amino and triethoxysilane functional groups, which can form a chemical bridging effect between inorganic materials (such as hydroxyl groups in bamboo or the surface of inorganic nanomaterials) and the phenolic resin matrix, thereby enhancing the interfacial bonding between the organic and inorganic phases. In addition, the modification effect of APTES can improve the dispersibility of nanoparticles in phenolic resins, reduce agglomeration, and improve the uniformity and stability of the composite material. The amino functional groups it contains can also chemically react with the hydroxyl or aldehyde groups in the phenolic resin, further increasing the crosslinking density and bonding strength of the system. KH-560 contains epoxy groups that can react with the hydroxyl or active hydrogen in the phenolic resin to introduce more crosslinking points, thereby improving the mechanical properties and thermal stability of the resin. KH-560 has both organic (epoxy) and inorganic (silyl) functional group structures, which helps the organic phenolic resin and inorganic reinforcing materials to react synergistically and enhance interfacial bonding. In addition, the introduction of epoxysilane helps to build a denser network structure, significantly improving the heat resistance, moisture resistance and aging resistance of the modified resin.

[0005] The introduction of graphene nanosheets into the phenolic resin system has the following main effects: (1) Enhancement of mechanical properties: Graphene nanosheets have excellent mechanical strength and high specific surface area, which can significantly improve the stress transfer ability of the system. Their addition can significantly improve the flexural strength, tensile strength and impact toughness of the phenolic resin, thereby enhancing the overall structural stability and damage resistance of the composite material; (2) Improvement of thermal stability and heat resistance: Graphene has extremely high thermal conductivity, which can effectively improve the thermal conductivity and thermal decomposition temperature of the phenolic resin, improve its dimensional stability and service life in high temperature environments, and thus expand its application range in the field of high temperature resistance.

[0006] It is of practical significance to prepare phenolic resin glue with high adhesion, high mechanical properties, excellent heat resistance and simple process. Summary of the Invention

[0007] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a high-performance phenolic resin glue for preparing engineering bamboo and a preparation method thereof, which has the advantages of high adhesion, high mechanical properties, excellent heat resistance and simple process.

[0008] To achieve the above objectives, the technical solution of the present invention is:

[0009] A high-performance phenolic resin adhesive for preparing engineering bamboo and a preparation method thereof are characterized in that: APTES and KH-560 are selected as organic silane substances, the main purpose of which is that APTES can form a bridging effect with inorganic materials (such as hydroxyl groups in bamboo and the surface of inorganic nanomaterials) and the phenolic resin matrix to enhance the organic-inorganic interface bonding, thereby improving the overall bonding strength; KH-560 contains epoxy groups, which can react with hydroxyl groups or active hydrogen in the phenolic resin, thereby introducing more crosslinking points and improving the mechanical properties and thermal stability of the resin. Graphene nanosheets are selected as inorganic nanoparticles, the main purpose of which is to enhance the mechanical properties, improve the thermal stability and optimize the interface properties. The method comprises the following steps: (1) adding APTES and KH-560 to an ethanol solution in a certain proportion; (2) adjusting the pH value thereof by acetic acid or ammonia water, and then stirring the solution by a magnetic stirrer; (3) adding graphene nanosheets and Tween 80 and continuing to stir to obtain a high-performance phenolic resin.

[0010] Furthermore, in step (1), APTES and KH-560 (mass ratio is 2:1 or 3:1 respectively) are added to an ethanol solution (the volume ratio of anhydrous ethanol to water is 4:1).

[0011] Furthermore, in step (2), the pH value of the solution is adjusted by acetic acid or ammonia to ensure that the pH of the solution is between 4 and 5, and the solution is placed in a magnetic stirrer and magnetically stirred at a rate of 700 to 1500 r / min for 0.5 to 1 hour;

[0012] Furthermore, in step (3), graphene nanosheets and dispersant Tween 80 are added to the mixed solution, and the mixture is stirred at a rate of 700 to 1500 r / min for 0.5 h to 1 h to obtain a high-performance phenolic resin.

[0013] Compared with the existing invention, the beneficial effects of the present invention are as follows:

[0014] APTES molecules contain both amino and triethoxysilane functional groups, which can form a chemical bridging effect between inorganic materials (such as hydroxyl groups in bamboo or the surface of inorganic nanomaterials) and the phenolic resin matrix, thereby enhancing the interfacial bonding force between the organic phase and the inorganic phase.

[0015] The modification effect of APTES can improve the dispersion of nanoparticles in phenolic resin, reduce agglomeration, and enhance the uniformity and stability of the composite material. Its amino functional groups can also chemically react with the hydroxyl or aldehyde groups in the phenolic resin, further increasing the crosslinking density and bonding strength of the system.

[0016] KH-560 contains epoxy groups that can react with hydroxyl groups or active hydrogen in phenolic resin to introduce more cross-linking points, thereby improving the mechanical properties and thermal stability of the resin.

[0017] KH-560 possesses both organic (epoxy) and inorganic (silane) functional groups, which facilitate a synergistic reaction between the organic phenolic resin and the inorganic reinforcing material, enhancing interfacial bonding. Furthermore, the introduction of epoxysilane helps to build a denser network structure, significantly improving the heat resistance, moisture resistance, and aging resistance of the modified resin.

[0018] Graphene nanosheets have excellent mechanical strength and high specific surface area, which can significantly improve the stress transfer ability of the system. Their addition can significantly improve the flexural strength, tensile strength and impact toughness of phenolic resin, thereby enhancing the overall structural stability and damage resistance of the composite material.

[0019] Graphene has extremely high thermal conductivity, which can effectively improve the thermal conductivity and thermal decomposition temperature of phenolic resin, improve its dimensional stability and service life in high temperature environments, and thus expand its application range in high temperature resistant fields. DETAILED DESCRIPTION

[0020] The present invention is described in detail below with reference to specific embodiments, but the protection scope of the present invention is not limited to the following embodiments.

[0021] A high-performance phenolic resin adhesive for preparing engineering bamboo and a preparation method thereof are characterized in that: APTES and KH-560 are selected as organic silane substances, the main purpose of which is that APTES can form a bridging effect with inorganic materials (such as hydroxyl groups in bamboo and the surface of inorganic nanomaterials) and the phenolic resin matrix to enhance the organic-inorganic interface bonding, thereby improving the overall bonding strength; KH-560 contains epoxy groups, which can react with hydroxyl groups or active hydrogen in the phenolic resin, thereby introducing more crosslinking points and improving the mechanical properties and thermal stability of the resin. Graphene nanosheets are selected as inorganic nanoparticles, the main purpose of which is to enhance the mechanical properties, improve the thermal stability and optimize the interface properties. The method comprises the following steps: (1) adding APTES and KH-560 to an ethanol solution in a certain proportion; (2) adjusting the pH value thereof by acetic acid or ammonia water, and then stirring the solution by a magnetic stirrer; (3) adding graphene nanosheets and Tween 80 and continuing to stir to obtain a high-performance phenolic resin.

[0022] Furthermore, in step (1), APTES and KH-560 (mass ratio is 2:1 or 3:1 respectively) are added to an ethanol solution (the volume ratio of anhydrous ethanol to water is 4:1).

[0023] Furthermore, in step (2), the pH value of the solution is adjusted by acetic acid or ammonia to ensure that the pH of the solution is between 4 and 5, and the solution is placed in a magnetic stirrer and magnetically stirred at a rate of 700 to 1500 r / min for 0.5 to 1 hour;

[0024] Furthermore, in step (3), graphene nanosheets and dispersant Tween 80 are added to the mixed solution, and the mixture is stirred at a rate of 700 to 1500 r / min for 0.5 h to 1 h to obtain a high-performance phenolic resin.

[0025] Example 1

[0026] APTES and KH-560 are added to an ethanol solution in a mass ratio of 2:1, and the pH of the solution is adjusted to 4-5 using acetic acid or aqueous ammonia. The mixed solution is placed in a magnetic stirrer and stirred at a rate of 700-1500 r / min for 0.5-1 hour. Subsequently, graphene nanosheets and dispersant Tween 80 are added to the mixed solution, and stirring is continued at a rate of 700-1500 r / min for 0.5-1 hour to obtain the high-performance phenolic resin adhesive. The added amounts of organosilane, ethanol solution, graphene nanosheets, and Tween 80 are 4wt%, 40wt%, 0.2wt%, and 0.5wt% of the mass of the phenolic resin, respectively.

[0027] Example 2

[0028] APTES and KH-560 are added to an ethanol solution in a mass ratio of 2:1, and the pH of the solution is adjusted to 4-5 using acetic acid or aqueous ammonia. The mixed solution is placed in a magnetic stirrer and stirred at a rate of 700-1500 r / min for 0.5-1 hour. Subsequently, graphene nanosheets and dispersant Tween 80 are added to the mixed solution, and stirring is continued at a rate of 700-1500 r / min for 0.5-1 hour to obtain the high-performance phenolic resin adhesive. The added amounts of organosilane, ethanol solution, graphene nanosheets, and Tween 80 are 4wt%, 40wt%, 0.6wt%, and 0.5wt% of the mass of the phenolic resin, respectively.

[0029] Example 3

[0030] APTES and KH-560 are added to an ethanol solution in a mass ratio of 2:1, and the pH of the solution is adjusted to 4-5 using acetic acid or aqueous ammonia. The mixed solution is placed in a magnetic stirrer and stirred at a rate of 700-1500 r / min for 0.5-1 hour. Subsequently, graphene nanosheets and dispersant Tween 80 are added to the mixed solution, and stirring is continued at a rate of 700-1500 r / min for 0.5-1 hour to obtain the high-performance phenolic resin adhesive. The added amounts of organosilane, ethanol solution, graphene nanosheets, and Tween 80 are 4wt%, 40wt%, 1wt%, and 0.5wt% of the mass of the phenolic resin, respectively.

[0031] Example 4

[0032] APTES and KH-560 are added to an ethanol solution in a mass ratio of 3:1, and the pH of the solution is adjusted to 4-5 using acetic acid or aqueous ammonia. The mixed solution is placed in a magnetic stirrer and stirred at a rate of 700-1500 r / min for 0.5-1 hour. Subsequently, graphene nanosheets and dispersant Tween 80 are added to the mixed solution, and stirring is continued at a rate of 700-1500 r / min for 0.5-1 hour to obtain the high-performance phenolic resin adhesive. The added amounts of organosilane, ethanol solution, graphene nanosheets, and Tween 80 are 4wt%, 40wt%, 0.2wt%, and 0.5wt% of the mass of the phenolic resin, respectively.

[0033] Example 5

[0034] APTES and KH-560 are added to an ethanol solution in a mass ratio of 3:1, and the pH of the solution is adjusted to 4-5 using acetic acid or aqueous ammonia. The mixed solution is placed in a magnetic stirrer and stirred at a rate of 700-1500 r / min for 0.5-1 hour. Subsequently, graphene nanosheets and dispersant Tween 80 are added to the mixed solution, and stirring is continued at a rate of 700-1500 r / min for 0.5-1 hour to obtain the high-performance phenolic resin adhesive. The added amounts of organosilane, ethanol solution, graphene nanosheets, and Tween 80 are 4wt%, 40wt%, 0.6wt%, and 0.5wt% of the mass of the phenolic resin, respectively.

[0035] Example 6

[0036] APTES and KH-560 are added to an ethanol solution in a mass ratio of 3:1, and the pH of the solution is adjusted to 4-5 using acetic acid or aqueous ammonia. The mixed solution is placed in a magnetic stirrer and stirred at a rate of 700-1500 r / min for 0.5-1 hour. Subsequently, graphene nanosheets and dispersant Tween 80 are added to the mixed solution, and stirring is continued at a rate of 700-1500 r / min for 0.5-1 hour to obtain the high-performance phenolic resin adhesive. The added amounts of organosilane, ethanol solution, graphene nanosheets, and Tween 80 are 4wt%, 40wt%, 1wt%, and 0.5wt% of the mass of the phenolic resin, respectively.

[0037] Adhesion performance test.

[0038] Table 1 Phenolic resin bonding performance values

[0039] The above embodiments are only specific embodiments of the present invention, and the protection scope of the present invention is not limited thereto. Any equivalent transformations, improvements, etc. made based on the concept of the present invention without departing from the essence of the technical solution of the present invention shall be included in the protection scope of the present invention.

[0040] Mechanical properties testing.

[0041] Table 2 Mechanical properties of phenolic resin

[0042] Heat resistance test

[0043] Table 3 Phenolic resin heat resistance data

Claims

1. A high-performance phenolic resin adhesive for preparing engineered bamboo and a preparation method thereof, characterized in that: APTES and KH-560 are selected as organosilane substances. The main purpose is that APTES can form a bridge with inorganic materials (such as hydroxyl groups in bamboo and the surface of inorganic nanomaterials) and the phenolic resin matrix to enhance the organic-inorganic interface bonding, thereby improving the overall bonding strength; KH-560 contains epoxy groups, which can react with hydroxyl groups or active hydrogen in the phenolic resin, thereby introducing more cross-linking points and improving the mechanical properties and thermal stability of the resin. Graphene nanosheets are selected as inorganic nanoparticles. The main purpose is to enhance mechanical properties, improve thermal stability and optimize interface properties. The following steps are included: (1) APTES and KH-560 are added to an ethanol solution in a certain proportion; (2) the pH value is adjusted by acetic acid or ammonia water, and the solution is stirred using a magnetic stirrer; (3) the graphene nanosheets and Tween 80 are added and continued to stir to obtain a high-performance phenolic resin.

2. The high-performance phenolic resin adhesive for preparing engineered bamboo and the preparation method thereof according to claim 1, characterized in that: In step (1), APTES and KH-560 (mass ratio of 2:1 or 3:1, respectively) are added to an ethanol solution (volume ratio of anhydrous ethanol to water is 4:1).

3. The high-performance phenolic resin adhesive for preparing engineered bamboo and the preparation method thereof according to claim 1, characterized in that: In step (2), the pH value is adjusted by acetic acid or ammonia water to ensure that the pH of the solution is between 4 and 5, and the solution is placed in a magnetic stirrer and magnetically stirred at a rate of 700 to 1500 r / min for 0.5 h to 1 h.

4. The high-performance phenolic resin adhesive for preparing engineered bamboo and the preparation method thereof according to claim 1, characterized in that: In step (3), graphene nanosheets and dispersant Tween 80 are added to the mixed solution, and stirred at a rate of 700 to 1500 r / min for 0.5 h to 1 h to obtain high-performance phenolic resin glue.

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